If $x \oplus y = 2x-4$ and $x \otimes y = x+4y$, find $(3 \oplus 3) \otimes 6$.
Solution: First, find $3 \oplus 3$ $ 3 \oplus 3 = (2)(3)-4$ $ \hphantom{3 \oplus 3} = 2$ Now, find $2 \otimes 6$ $ 2 \otimes 6 = 2+(4)(6)$ $ \hphantom{2 \otimes 6} = 26$.